Switch attachment for cluster electric fixtures.



PATENTED AUG. 2, 1904.

W. L; BRADSHAW.

SWITCH ATTACHMENT FOR CLUSTER ELECTRIC FIXTURES.

APPLICATION FILED MAY 27, 1904.

H0 MODEL.

vllllllll VNMMW MAT- 455555.

UNTTED STATES Patented August 2, 1904.

PATENT UFFICE.

SWITCH ATTACHMENT FOR CLUSTER ELECTRIC FIXTURES SPECIFICATION forming part of Letters Patent No. 766,319, dated August 2,1904.

Application filed May 27, 1904.

To a, 71171-0711, it nmy concern:

Be it known that 1, human L. BRADSHAW, a citizen of the United States, and a resident of Cambridge, in the county of Middlesex, State of Massachusetts, have invented certain new and useful Improvements in Switch Attachments for Cluster Electric Fixtures; and

' I do hereby declare the following to be a full and exact description of my said invention. My invention has particular reference to cluster lixtures mounted or suspended in high orinaccessible places, whereby their operation by means of the ordinary key is precluded.

The customary operation of such fixtures is by 1 means of an electric cord extension from the cluster-box provided with a press-button w ithin easy reach of the operator. This cord passes through the base-plate or bottom of the box and connects with the main circuit at a point within. To prevent its being torn from the main lighting-wires at the pomt of attachment therewith, it is usual to simply knot the cord within the box, the idea being that the knot coacting with the bottom of the box serves to maintain the connections intact by relieving them of any strain. An inherent fault, however, with this expedient for relieving the strain is that jerks on the cord in the careless operation of the press-button generally have the effect of pulling off the base-plate of the cluster-box, to the disfigurement of the fixture and to the injury of the strain-relieving means. Thereupon the strain of any further pull upon the switch-cord may result in tearing the cord from its attachment to the main 1 lighting-wire.

My invention relates to means for relieving I the points of uncture of the switch-cord and the main circuit of the strain of any pull upon the switch-cord and for causing said strains to fall not upon the base-plate or bottom of the cluster-box, but upon the box itself. In this Way disfigurement of the fixture by reason of a disconnected base-plate or the subsequent injury of the circuit by reason of the loss of effectiveness of the switch-cord support is, all avoided.

My invention not only serves to relieve the Serial No. 209,999- (No model.)

I base-plate from strain by pull on the switchcord, but effectuallypreventslooseningordisplacement of the plate by any other means.

Other features of my invention will presently appear upon the description of my device in connection with the drawings, in which--- Figure l is a cross-sectional elevation of the assembled cluster-box with my attachment; Fig.2, a plan of the same on the line a a of Fig. 1. Fig. 3 is a detail view in plan of my attachment; Fig. i, an elevation of the same; Fig. 5, a plan view of the base-plate.

Referring to Figs. 1 andQ, the box A is represented as having the customary base-plate or bottom B removably secured thereto by the customary bayonet-joint. The box is shown 1 as provided with a threaded extension C for its attachment to a suitable support and for the passage of the electric wires. It is shown l as provided with threaded nipples D for the attachment of lamps or other devices and for the passage of the wires to such devices. The base-plate I is provided with an opening E in the bottom thereof for the passage of the switch-cord. The opening E is fitted with the usual bushing F for preventing the abrasion l of the cord by the plate B. It is to be noted l that the walls r have the usual taper.

Referring now to Figs. 3 and a, my attachment is indicated at H and is shown in the form of a spider, with a central tubular extension I, the legs of the spider being indicated at J. I prefer to make this attachment in a single integral piece, preferably of castiron. This is not essential, however, as it 1 may be an assemblage of several elements and 1 may be made of a variety of materials and not necessarily entirely of the same material. The tubular extension 1 is shown as extendl 1 ing about to the plate B and is internally threaded to engage the threaded bushing F. It may not, however, extend to the plate, 01', on the other hand, may extend through the same, in such instances the bushing being designed, however, to securely engage the same. The extension is of suflicientinternal diameter to permit the passage of the switch-cord. i The length of the arms J of the spider should be greater than the radius of the base-plate.

or, in other words, should be sufiiciently long to cause the spider when inserted in the clusterbox to rest in contact with the tapering walls of the box. The ends of the arms J are preferably slightly tapered, as shown at K, in order to provide a better contacting surface between them and the box.

In operation my device is-inserted in the box, as shown in Fig. l, the spider-arms resting against the tapering walls thereof and the extension H projecting downward to be threaded to the bushing at the opening in the base-plate, the bushing serving to center and maintain the spider erect and in true alinement. The switch-cord is shown as knotted, as at L, and this knot is immediately above the upper surface of the spider-arms. It is evident that any pull upon the switch-cord causes the knot to press against the spider, and as the spider is supported by the box itself and not by the base-plate there is no possibility of the latter being displaced. Furthermore, the engagement of the spider with the box is such that no amount of force applied to the spider could displace the same without the destruction of the box so long as the spider is maintained erect by the bushing.

In order to insure a truly-centered hole in the base plate for the engagement of the threaded spider projection with the bushing, as above mentioned, I provide the base-plate in its manufacture with a circular indentation,

as shown at M in Fig. 5, whereupon for the use of such plate with my device it is simply necessary to knock out the portion of the plate described by the indentation.

Whereas I have shown the switch-cord engaging the spider by means of the usual knot, my invention is not limited to such means of engagement, but may engage the cord by other meanssuch, for example, as form the subject-matter of my copending application, Serial No. 171,309. Neither is my attachment limited in use to the particular form of clusterbox described, as it is obvious that it may have a much wider use.

What I claim as my invention is l. The device herein described, comprising in combination with a cluster-box, cord-supporting and strain-relieving means therein in engagement with said box.

2. The device herein described, comprising in combination with a cluster-box, cord-supporting and strain-relieving means therein in engagement with the walls of said box.

3. The device herein described, comprising in combination with a cluster-box, a plate, contacting at points with the interior of the box to prevent withdrawal when in use, said plate having means of engagement with the cord to relieve the strain on the terminals thereof, and means for preventing accidental displacement.

4. The device herein described, comprising 5 in combination with a cluster-box, a plate of a shape to be inserted through the base thereof, and to engage the interior walls of the box when in operative position within the same, said plate having means of engagement with the cord to relieve the strain on the terminals thereof and means to maintain it in operative position.

5. The device herein described, comprising in combination with a cluster-box and its removable base-plate, a device of a shape to be inserted through the base of the box when the base-plate is removed, and to engage the interior walls of the box when in operative position within the same, said device having a hole for the passage of the cord and a tubular extension from said hole for engaging the base-plate of the box.

6. The device herein described, comprising a cluster-box, a removable base-plate therefor, having a cord-passage and a bushing for said passage, a device of a shape to be inserted through the base of the box when the baseplate is removed, and to engage the interior walls of the box when arranged in operative position within the same, said device having a passage for the cord, and a tubular extension from said passage engaging the bushing in base-plate, whereby the device is prevented from accidental displacement in operation.

7. The device herein described, comprising a cluster-box, a removable base therefor having a cord-passage, a spider of a size to be inserted through the base of the box when the base-plate is removed, and to engage with its arms the interior walls of the box when arranged in operative position within the same, said spider having means of engagement with the cord and means of engagement with the base-plate at the opening therein to prevent accidental displacement in operation.

8. The device herein described, comprising a cluster-box, a removable base-plate therefor, having a cord-passage and a bushing for said passage, a device of a shape to be inserted through the base of the box when the baseplate is removed, and to engage the interior walls of the box when arranged in operative position within the-same, said device having a passage for the cord, and a tubular extension from said passage threaded to engage the bushing in base-plate, whereby the device is prevented from accidental displacement in operation.

WALTER L. BRADSHAWV.

In presence of J. M. DOLAN, M. V. FOLEY. 

